Polyoxometalate-assisted development of Enzyme@Metal-organic frameworks catalysts – EPONYME

Enzymes are highly efficient eco-friendly catalysts but often need immobilization on solid supports for practical use. Metal-organic frameworks (MOFs) are effective matrices for this purpose, as enzymes@MOFs can be obtained by forming the MOF around the enzyme, offering unique protection to the biomolecules and resulting in stable and recyclable materials. Nevertheless, this approach requires conditions that preserve the integrity of the enzyme (water, Tmax ~45 °C). Moreover, such process is constrained to a limited number of MOFs and remains poorly understood, as well as challenging to analyze. This is due to the difficulty of crystallizing biomolecule@MOF composites and to image proteins and MOFs. Polyoxometalates (POMs) are known to facilitate protein crystallization. urthermore, POMs have been combined with MOFs, forming POM@MOF hybrids that have been the subject of extensive investigation with regard to their catalytic properties. Nevertheless, their potential role in the formation of protein@MOF composites is fully unexplored.
The aim of this proposal is to combine enzymes, POMs and MOFs to elaborate (enzyme,POM)@MOF composites where the enzyme and the POM are encapsulated within the MOF framework. The objectives are to take advantage of the biocatalytic properties of the enzyme, of the dual role of the POM (crystallization agent and co-catalyst) and of the adsorption properties of the MOF to develop high-performance (enzyme,POM)@MOF catalysts. Moreover, the 3D microstructure and assembly under humid conditions of these materials will be investigated using advanced environmental electron microscopy techniques. This will enable to evidence the accessibility of the catalytic sites, the inter-component interactions and providing insights on the assembly and nucleation-growth mechanisms of these composites, an underexplored area.